Functionalized PFPE materials currently available in the market, in particular those commercialized by Solvay Solexis, are generally derivatives obtained from PFPE comprising —CF2CH2OH end groups. Chemistry of —CH2OH group is generally used for introducing further functional moieties, notably via ether, ester, urethane or other similar bridging groups. Common feature of this chemistry is that the bridge between the PFPE chain and the (hydrogenated) functionality comprises a —CF2CH2O— moiety. The —CH2— group sandwiched between a —CF2— group and an oxygen atom has been possibly identified as possible source of thermal failures in these materials, which limits indeed thermal stability of PFPE functional derivatives containing the same.
The need was thus felt in the art for a manufacturing process for a new class of functional perfluoropolyether derivatives free from said weak —CF2 CH2O— moiety but comprising highly thermally stable bridging groups.